Controlled impact of a disk on a water surface: cavity dynamics

By R. Bergmann, D. Meer, Stephan Gekle, A. Bos, Detlef Lohse. Journal of Fluid Mechanics, 2008

172 citations recorded by the source corpus.

In this paper we study the transient surface cavity which is created by the controlled impact of a disk of radius h0 on a water surface at Froude numbers below 200. The dynamics of the transient free surface is recorded by high-speed imaging and compared to boundary integral simulations giving excellent agreement. The flow surrounding the cavity is measured with high-speed particle image velocimetry and is found to also agree perfectly with the flow field obtained from the simulations. We present a simple model for the radial dynamics of the cavity based on the collapse of an infinite cylinder. This model accounts for the observed asymmetry of the radial dynamics between the expansion and the contraction phases of the cavity. It reproduces the scaling of the closure depth and total depth of the cavity which are both found to scale roughly as ∝ Fr1/2 with a weakly Froude-number-dependent prefactor. In addition, the model accurately captures the dynamics of the minimal radius of the cavity and the scaling of the volume Vbubble of air entrained by the process, namely, Vbubble/h03∝(1 + 0.26Fr1/2)Fr1/2.

Subfields: Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/57e457b7bd21a716ba3ccb2168fcd8d63160093f

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In Computational Mechanics

1. J. Gordillo
2. Stephan Gekle

Citations in the corpus

• Generation and breakup of Worthington jets after cavity collapse. Part 1. Jet formation (2009, methodology): “The experimental realization of the setup to which the numerical simulations presented are referred, is described by Bergmann et al. (2006, 2009); Gekle et al. (2008, 2009a), who show that boundary-integral simulations are in excellent agreement with experiments. In addition, potential flow numerica”